Tanuki Transplanter [Kamigawa: Neon Dynasty Commander]

Whenever Tanuki Transplanter or equipped creature attacks, add an amount of G equal to its power. Until end of turn, you don't lose this mana as steps and phases end.
Reconfigure 3 (3: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)